zotero/chrome/chromeFiles/content/scholar/xpcom/schema.js
Dan Stillman 14e3b05ca4 Separated schema into two files, system.sql and user.sql -- the former contains tables that can be wiped and reinitialized at any time *as long as ids are kept the same* (like scrapers.sql), whereas the latter contains user data that has to be migrated from one version to the other with transition steps
This should make development much easier, as we can, for example, add 80 item types without having to write transition steps

Pretty sure this won't delete anyone's data. Might want to test that theory, though.
2006-09-10 20:08:59 +00:00

444 lines
12 KiB
JavaScript

Scholar.Schema = new function(){
var _dbVersions = [];
var _schemaVersions = [];
var _repositoryTimer;
this.updateSchema = updateSchema;
this.updateScrapersRemote = updateScrapersRemote;
this.stopRepositoryTimer = stopRepositoryTimer;
/*
* Checks if the DB schema exists and is up-to-date, updating if necessary
*/
function updateSchema(){
if (SCHOLAR_CONFIG['DB_REBUILD']){
if (confirm('Erase all user data and recreate database from schema?')){
_initializeSchema();
return;
}
}
var dbVersion = _getDBVersion('user');
// 'schema' check is for old (<= 1.0b1) schema system
if (!dbVersion && !_getDBVersion('schema')){
Scholar.debug('Database does not exist -- creating\n');
_initializeSchema();
return;
}
// Old schema system
if (!dbVersion){
dbVersion = 0;
}
var schemaVersion = _getSchemaSQLVersion('user');
if (dbVersion > schemaVersion){
throw("Zotero user DB version is newer than SQL file");
}
Scholar.DB.beginTransaction();
try {
// If user DB version is less than schema file, create or update
if (dbVersion < schemaVersion){
_migrateUserSchema(dbVersion);
}
_updateSchema('system');
_updateSchema('scrapers');
Scholar.DB.commitTransaction();
}
catch(e){
Scholar.debug(e);
Scholar.DB.rollbackTransaction();
throw(e);
}
return;
}
/**
* Send XMLHTTP request for updated scrapers to the central repository
*
* _force_ forces a repository query regardless of how long it's been
* since the last check
**/
function updateScrapersRemote(force){
if (!force){
// Check user preference for automatic updates
if (!Scholar.Prefs.get('automaticScraperUpdates')){
Scholar.debug('Automatic scraper updating disabled -- not checking repository', 4);
return false;
}
// Determine the earliest local time that we'd query the repository again
var nextCheck = new Date();
nextCheck.setTime((parseInt(_getDBVersion('lastcheck'))
+ SCHOLAR_CONFIG['REPOSITORY_CHECK_INTERVAL']) * 1000); // JS uses ms
var now = new Date();
// If enough time hasn't passed, don't update
if (now < nextCheck){
Scholar.debug('Not enough time since last update -- not checking repository', 4);
// Set the repository timer to the remaining time
_setRepositoryTimer(Math.round((nextCheck.getTime() - now.getTime()) / 1000));
return false;
}
}
// If transaction already in progress, delay by a few seconds
if (Scholar.DB.transactionInProgress()){
Scholar.debug('Transaction in progress -- delaying repository check', 4)
_setRepositoryTimer(30);
return false;
}
// Get the last timestamp we got from the server
var lastUpdated = _getDBVersion('repository');
var url = SCHOLAR_CONFIG['REPOSITORY_URL'] + '/updated?'
+ (lastUpdated ? 'last=' + lastUpdated + '&' : '')
+ 'version=' + Scholar.version;
Scholar.debug('Checking repository for updates (' + url + ')');
var get = Scholar.Utilities.HTTP.doGet(url, _updateScrapersRemoteCallback);
// TODO: instead, add an observer to start and stop timer on online state change
if (!get){
Scholar.debug('Browser is offline -- skipping check');
_setRepositoryTimer(SCHOLAR_CONFIG['REPOSITORY_RETRY_INTERVAL']);
}
}
function stopRepositoryTimer(){
if (_repositoryTimer){
Scholar.debug('Stopping repository check timer');
_repositoryTimer.cancel();
}
}
/////////////////////////////////////////////////////////////////
//
// Private methods
//
/////////////////////////////////////////////////////////////////
/*
* Retrieve the DB schema version
*/
function _getDBVersion(schema){
// Default to schema.sql
if (!schema){
schema = 'schema';
}
if (_dbVersions[schema]){
return _dbVersions[schema];
}
if (Scholar.DB.tableExists('version')){
var dbVersion = Scholar.DB.valueQuery("SELECT version FROM "
+ "version WHERE schema='" + schema + "'");
_dbVersions[schema] = dbVersion;
return dbVersion;
}
return false;
}
/*
* Retrieve the version from the top line of the schema SQL file
*/
function _getSchemaSQLVersion(schema){
if (!schema){
throw ('Schema type not provided to _getSchemaSQLVersion()');
}
var schemaFile = schema + '.sql';
if (_schemaVersions[schema]){
return _schemaVersions[schema];
}
var file = Components.classes["@mozilla.org/extensions/manager;1"]
.getService(Components.interfaces.nsIExtensionManager)
.getInstallLocation(SCHOLAR_CONFIG['GUID'])
.getItemLocation(SCHOLAR_CONFIG['GUID']);
file.append(schemaFile);
// Open an input stream from file
var istream = Components.classes["@mozilla.org/network/file-input-stream;1"]
.createInstance(Components.interfaces.nsIFileInputStream);
istream.init(file, 0x01, 0444, 0);
istream.QueryInterface(Components.interfaces.nsILineInputStream);
var line = {};
// Fetch the schema version from the first line of the file
istream.readLine(line);
var schemaVersion = line.value.match(/-- ([0-9]+)/)[1];
istream.close();
_schemaVersions[schema] = schemaVersion;
return schemaVersion;
}
/*
* Load in SQL schema
*
* Returns the contents of an SQL file for feeding into query()
*/
function _getSchemaSQL(schema){
if (!schema){
throw ('Schema type not provided to _getSchemaSQL()');
}
var schemaFile = schema + '.sql';
// We pull the schema from an external file so we only have to process
// it when necessary
var file = Components.classes["@mozilla.org/extensions/manager;1"]
.getService(Components.interfaces.nsIExtensionManager)
.getInstallLocation(SCHOLAR_CONFIG['GUID'])
.getItemLocation(SCHOLAR_CONFIG['GUID']);
file.append(schemaFile);
// Open an input stream from file
var istream = Components.classes["@mozilla.org/network/file-input-stream;1"]
.createInstance(Components.interfaces.nsIFileInputStream);
istream.init(file, 0x01, 0444, 0);
istream.QueryInterface(Components.interfaces.nsILineInputStream);
var line = {}, sql = '', hasmore;
// Skip the first line, which contains the schema version
istream.readLine(line);
//var schemaVersion = line.value.match(/-- ([0-9]+)/)[1];
do {
hasmore = istream.readLine(line);
sql += line.value + "\n";
} while(hasmore);
istream.close();
return sql;
}
/*
* Create new DB schema
*/
function _initializeSchema(){
Scholar.DB.beginTransaction();
try {
Scholar.DB.query(_getSchemaSQL('user'));
_updateDBVersion('user', _getSchemaSQLVersion('user'));
Scholar.DB.query(_getSchemaSQL('system'));
_updateDBVersion('system', _getSchemaSQLVersion('system'));
Scholar.DB.query(_getSchemaSQL('scrapers'));
_updateDBVersion('scrapers', _getSchemaSQLVersion('scrapers'));
Scholar.DB.commitTransaction();
}
catch(e){
Scholar.debug(e, 1);
Scholar.DB.rollbackTransaction();
alert('Error initializing Zotero database'); // TODO: localize
throw(e);
}
}
/*
* Update a DB schema version tag in an existing database
*/
function _updateDBVersion(schema, version){
_dbVersions[schema] = version;
var sql = "REPLACE INTO version (schema,version) VALUES (?,?)";
return Scholar.DB.query(sql, [{'string':schema},{'int':version}]);
}
function _updateSchema(schema){
var dbVersion = _getDBVersion(schema);
var schemaVersion = _getSchemaSQLVersion(schema);
if (dbVersion == schemaVersion){
return;
}
else if (dbVersion < schemaVersion){
Scholar.DB.beginTransaction();
try {
Scholar.DB.query(_getSchemaSQL(schema));
_updateDBVersion(schema, schemaVersion);
Scholar.DB.commitTransaction();
}
catch (e){
Scholar.debug(e, 1);
Scholar.DB.rollbackTransaction();
alert('Error updating Zotero database'); // TODO: localize
throw(e);
}
return;
}
else {
throw("Zotero '" + schema + "' DB version is newer than SQL file");
}
}
/**
* Process the response from the repository
**/
function _updateScrapersRemoteCallback(xmlhttp){
if (!xmlhttp.responseXML){
if (xmlhttp.status>1000){
Scholar.debug('No network connection', 2);
}
else {
Scholar.debug('Invalid response from repository', 2);
}
_setRepositoryTimer(SCHOLAR_CONFIG['REPOSITORY_RETRY_INTERVAL']);
return false;
}
var currentTime = xmlhttp.responseXML.
getElementsByTagName('currentTime')[0].firstChild.nodeValue;
var updates = xmlhttp.responseXML.getElementsByTagName('translator');
Scholar.DB.beginTransaction();
// Store the timestamp provided by the server
_updateDBVersion('repository', currentTime);
// And the local timestamp of the update time
var d = new Date();
_updateDBVersion('lastcheck', Math.round(d.getTime()/1000)); // JS uses ms
if (!updates.length){
Scholar.debug('All scrapers are up-to-date');
Scholar.DB.commitTransaction();
_setRepositoryTimer(SCHOLAR_CONFIG['REPOSITORY_CHECK_INTERVAL']);
return false;
}
for (var i=0, len=updates.length; i<len; i++){
try {
_scraperXMLToDBQuery(updates[i]);
}
catch (e) {
Scholar.debug(e, 1);
Scholar.DB.rollbackTransaction();
var breakout = true;
break;
}
}
if (!breakout){
Scholar.DB.commitTransaction();
_setRepositoryTimer(SCHOLAR_CONFIG['REPOSITORY_CHECK_INTERVAL']);
}
}
/**
* Set the interval between repository queries
*
* We add an additional two seconds to avoid race conditions
**/
function _setRepositoryTimer(interval){
if (!interval){
interval = SCHOLAR_CONFIG['REPOSITORY_CHECK_INTERVAL'];
}
var fudge = 2; // two seconds
var displayInterval = interval + fudge;
var interval = (interval + fudge) * 1000; // convert to ms
if (!_repositoryTimer || _repositoryTimer.delay!=interval){
Scholar.debug('Setting repository check interval to ' + displayInterval + ' seconds');
_repositoryTimer = Components.classes["@mozilla.org/timer;1"].
createInstance(Components.interfaces.nsITimer);
_repositoryTimer.initWithCallback({
// implements nsITimerCallback
notify: function(timer){
Scholar.Schema.updateScrapersRemote();
}
}, interval, Components.interfaces.nsITimer.TYPE_REPEATING_SLACK);
}
}
/**
* Traverse an XML scraper node from the repository and
* update the local scrapers table with the scraper data
**/
function _scraperXMLToDBQuery(xmlnode){
var sqlValues = [
{'string':xmlnode.getAttribute('id')},
{'string':xmlnode.getAttribute('lastUpdated')},
{'string':xmlnode.getAttribute('type')},
{'string':xmlnode.getElementsByTagName('label')[0].firstChild.nodeValue},
{'string':xmlnode.getElementsByTagName('creator')[0].firstChild.nodeValue},
// target
(xmlnode.getElementsByTagName('target').item(0) &&
xmlnode.getElementsByTagName('target')[0].firstChild)
? {'string':xmlnode.getElementsByTagName('target')[0].firstChild.nodeValue}
: {'null':true},
// detectCode can not exist or be empty
(xmlnode.getElementsByTagName('detectCode').item(0) &&
xmlnode.getElementsByTagName('detectCode')[0].firstChild)
? {'string':xmlnode.getElementsByTagName('detectCode')[0].firstChild.nodeValue}
: {'null':true},
{'string':xmlnode.getElementsByTagName('code')[0].firstChild.nodeValue}
]
var sql = "REPLACE INTO translators VALUES (?,?,?,?,?,?,?,?)";
return Scholar.DB.query(sql, sqlValues);
}
/*
* Migrate user schema from an older version, preserving data
*/
function _migrateUserSchema(fromVersion){
//
// Change this value to match the schema version
//
var toVersion = 1;
if (toVersion != _getSchemaSQLVersion('user')){
throw('User schema file version does not match version in _migrateUserSchema()');
}
Scholar.debug('Updating user tables from version ' + fromVersion + ' to ' + toVersion);
Scholar.DB.beginTransaction();
try {
// Step through version changes until we reach the current version
//
// Each block performs the changes necessary to move from the
// previous revision to that one.
for (var i=fromVersion + 1; i<=toVersion; i++){
if (i==1){
Scholar.DB.query("DELETE FROM version WHERE schema='schema'");
}
}
_updateDBVersion('user', i-1);
Scholar.DB.commitTransaction();
}
catch(e){
Scholar.debug(e);
alert('Error migrating Zotero database');
throw(e);
}
}
}